Question

Which of the following pairs of elements could possibly be found in the same group on the periodic table? (2 points)

A forms a 2+ ion; B is in group 2.

A is a noble gas; B forms a 1− ion.

A has 3 valence electrons; B is a halogen in group 17.

A forms a 2− ion; B is a metal in group 2.

Answer 1

The answer is the first choice. This is because only molecules in the second group have a charge of 2+ (because they want to lose 2 electrons).